1. Field of the Invention
The present invention relates to a heat dissipation device, particularly to an improved heat dissipation device suitable for use with a CPU.
2. Description of the Related Art
A conventional fan, as shown in FIG. 1, includes a fan frame 10 and a blade structure 20. The fan frame 10 has a circular air inlet 11 matching the blade structure 20 and an air outlet 12. The blade structure 20 further includes a hub 21, a base plate 22, and a plurality of blades 23 formed thereon. The blades 23 transfer the intake airflow parallel to the axial direction of the blade structure 20 to the outward airflow along the radial direction of the hub 21, and the outward airflow is then expelled.
Due to the increasing production of electronic components and in order to enhance heat dissipation efficiency, it is possible to enlarge the airflow passage to increase the airflow amount. However, the method described above can not be implemented in a limited space. As well, based on experience or a distribution diagram of equivalent pressure (not shown) obtained by experiment, an air outflow in a curved portion 14 of the fan frame 10 will further interfere with the intake airflow of the air inlet and the later air outflow due to adverse airflow, creating many problems such as unbalanced air outflow, noise, and decreased air outflow.
Therefore, it is necessary to have a novel heat dissipation device to solve the foregoing problems and to increase the air outflow to enhance heat dissipation efficiency.
An object of the invention is to provide a heat dissipation device, wherein the air inlet has a noncircular indentation in the vicinity of the curved portion corresponding to the airflow passage. This indentation effectively increases the air outflow and static pressure of the airflow expelled from the heat dissipation device.
Another object of the invention is to provide a heat dissipation device which improves the interference between the intake airflow and the air outflow both in the air inlet and the air outlet, and effectively increases the air outflow so as to enhance efficiency under the same rotation speed of the fan.
The first embodiment of the invention disposes a heat dissipation device having a centrifugal fan. The fan includes a fan frame and blade structure. The blade structure is disposed in the recess of the fan frame. This airflow passage is the route through which the air flows from the air inlet to the air outlet. There is no definite configuration for the blade structure, for example, a centrifugal blade structure having a hub, a base plate, and a plurality of blades formed on the base plate.
The fan frame also includes an air inlet and outlet, or the fan frame can alternatively be comprised of a pedestal and a cap. The cap has an air inlet, and the pedestal has an air outlet. It should be noted that the air inlet of the invention has an indentation in the vicinity of the curved portion of the fan frame, and the indentation extends toward the air outlet such that a part of the air inlet has a non-arc configuration while the other part has an arc configuration. The indentation is used to dissipate the adverse airflow so as to balance the air outflow and enhance the efficiency of heat dissipation. According to measurements, the fan of the invention increases air outflow by at least 20% compared to that of a conventional fan (the configuration of the airflow inlet is circular) with the same dimensions as the present fan. Therefore, the invention can obtain the same air outflow with a lower rotation speed, and thus suppress the noise.
The second embodiment of the invention is a heat dissipation module including a blade structure The heat dissipation module is disposed adjacent to a heat source; for example, the heat dissipation module is disposed on the lateral side of a central processing unit (CPU). The second embodiment of the invention includes a fan frame and a blade structure, wherein the fan frame has an airflow outlet and a non-circular airflow inlet, and alternatively has a cap.
The blade structure is not limited to a certain configuration; it can be an axial or a centrifugal configuration. In this embodiment, the blade structure has a centrifugal blade configuration, which includes a hub, a base plate and a plurality of blades formed on the base plate. The blade structure is disposed in the recess of the fan frame. The airflow passage is the route through which the air flows from the air inlet to the air outlet. The blades transfer the intake airflow parallel to the axial direction of the blade structure to the outward airflow along the radial direction of the hub, and the outward airflow is then expelled.
Similar to the first embodiment, the curved portion of the fan frame in the second embodiment has an indentation. The indentation extends toward the air outlet such that a part of the air inlet has a non-arc configuration. The indentation dissipates the adverse airflow in the airflow passage in the vicinity of the curved portion to prevent the adverse airflow from interfering with the intake airflow or with the later air outflow, such that the air outflow is more balanced and increased.
The heat dissipation module further includes a heat-conduction plate extended from a lateral wall of the fan frame to load a heat source; for example, a CPU disposed on the heat-conduction plate is adjacent to the heat dissipation module, such that the heat-conduction plate absorbs the heat from the CPU. Additionally, the air outlet of the heat dissipation module has a number of fins and the heat-conduction plate has a heat pipe adjacent to the heat source and extended to the fins. The heat pipe is formed to conduct the heat of the heat-conduction plate to the fins such that the blowing of the blade structure can dissipate the heat from the heat source.